why does my 1972 starflight 125 have points?

[clearwatguy]

according to everything i have been able to find this should have a sensor... including its own distributor cap which has a sticker on top that says "Set sensor gap to .028 yet under the flywheel i have a stator and cap assembly and beneith that a wave washer and rotor and under that i have a set of dual points with spring loaded arms, rubbing blocks, and contact points. i double checked the plug on the power head and it is a 125 horse... is this a freak of nature? it has a single coil, and a "pulse pack" the pulse pack has some odd wiring that was done to make it fit the motor i think this because it does not have a standard connector on it, the connector has fewer wires and the wires that are missing are connected to the distribution block from the powerhead side of the connector. the connector is a marine water tight plug and it all was done very well not sloppy looks professional. i just dont get the points everything i have been reading suggests they should not be there!

 

[Faztbullet]

Re: why does my 1972 starflight 125 have points?

Sounds like a 100 hp ignition system, maybe engine "popped" years ago and someone used 100 hp crank and found it used different ignition than 125.

 

[emdsapmgr]

Re: why does my 1972 starflight 125 have points?

Replacement powerhead? Check the casting plug in the top of the block for proper powerhead identification.

 

[F_R]

Re: why does my 1972 starflight 125 have points?

The way I see it, there are only a couple of things that could have happened.

1: It really is a 125hp, and somebody has swapped the crankshaft and igniton system from a smaller motor.

2: It really is an 85hp or 100hp and somebody has swapped the ID plug in the powerhead (it IS possible to get them out without damaging them , you know)

The only way I know of to be certain is to pull a cylinder head and check the bore. A 125 is 3.5" bore. A 100 is 3.375" bore. A 85 is also 3.375"

 

[clearwatguy]

Re: why does my 1972 starflight 125 have points?

The way I see it, there are only a couple of things that could have happened.

1: It really is a 125hp, and somebody has swapped the crankshaft and igniton system from a smaller motor.

2: It really is an 85hp or 100hp and somebody has swapped the ID plug in the powerhead (it IS possible to get them out without damaging them , you know)

The only way I know of to be certain is to pull a cylinder head and check the bore. A 125 is 3.5" bore. A 100 is 3.375" bore. A 85 is also 3.375"

its a 3.75 inch bore i checked it with a bore gauge 3 times. i guess it was blown and bored over at some point and they were unable to get ahold of the proper crank shaft so they substituted. i have a spare motor that was blown that came with the boat it too is a 125 and it has the sensor under the flywheel. i guess it doesnt matter now that i have it running it runs damn good, pushes a late 70's mfg 17 foot trihull through the water at about 42 (according to my gps) i would just like to set the points to optimum. also now that we know all this does that mean the timing info, spark plugs etc from the factory is not accurite?

 

[F_R]

Re: why does my 1972 starflight 125 have points?

its a 3.75 inch bore i checked it with a bore gauge 3 times. i guess it was blown and bored over at some point and they were unable to get ahold of the proper crank shaft so they substituted. i have a spare motor that was blown that came with the boat it too is a 125 and it has the sensor under the flywheel. i guess it doesnt matter now that i have it running it runs damn good, pushes a late 70's mfg 17 foot trihull through the water at about 42 (according to my gps) i would just like to set the points to optimum. also now that we know all this does that mean the timing info, spark plugs etc from the factory is not accurite?

3.75" bore?? Wow!! I didn't know they made them that big. Or that you could bore one 1/4" oversize without going through the cylinder liner.

 

[clearwatguy]

Re: why does my 1972 starflight 125 have points?

3.75" bore?? Wow!! I didn't know they made them that big. Or that you could bore one 1/4" oversize without going through the cylinder liner.

lol omg im sorry typo 3.55 not 3.75 it would be compressing the water jacket at 3.75 lol

speaking of that though is it normal for the walls to be so thin? ok admittedly most of my 2 stroke experience is from air cooled dirt bike engines and i suppose with fresh water coursing through they dont need to be as thick but they seem thin...

 

[clearwatguy]

Re: why does my 1972 starflight 125 have points?

ok where to start lol i got the manual and i did the link and synch didnt seem to do much good. i pulled the carbs and rebuilt them, helped a little i went from 15 mph on my gps to 18 mph. i tried a more aggressive prop which put us to 20 mph. i tried to time the engine to no avail the timing light on number one cyl, pointed at the arrow mounted on the block to alighn the marks with and there were no marks showing up (i put white paint on the 5 degre and 26 degree marks even but all my light revealed was mare metal lol...) i ran the light around about 4 inches from where the timing pointer is and there were the marks... must be because its not the right crank shaft and ignition system?

now keep in mind it always starts good and it runs ok at low speeds but has no top end...

out of desperation i got her going full tilt (lol full tilt it like 22 mph on a 17 foot tri hull, a couple times i have looked to make sure i didnt unhook the trailer from the truck and leave it attatched to the boat lol)

so anyway i turn the helm over to my girl friend its plogging along missing popping and drooling gasoline out of the bottom corner of the air intake. i took my wrench and broke the timing adjust backing nut loose and kneeled in front of the engine under way i started to advance the timing a hair at a time so as not to get preignition, 1/4 turn nothing, 1/2 turn nothing, 5 turns and it started to pickup like it was running faster, im deaf from the carb noise in my ear so i can even hear it popping and sneezing so i sit back and then i can hear it cough but not as bad, so forward i go again and advance it a little more and it speeds up once again a little more a little more and its not sneezing so bad now i can tell because the motor isnt jumping back and fourth against the steering rod so much just here and there. so i open the carb screws engine picks up some more... a little more advance on the timing and a little more gas and its not sneezing its not drooling out of the carbs its running..... dare i say it? good!!! i stand up and the first look behind us o see its not this big roll of water as wide as the boat with blue smoke rolling off the top its a huge cavity of water thats shaped like an arrow! holy crap!!! this thing is going!!!!!! i dashed to the gps and it was regeristing 48 mph!!!!!!!! the engine was running BETTER not perfect it still coughs here and there but not bad!!! i took her off plane slow amd then down to idle speed and it idles PERFECTLY... i shut it off and it restarted!!! im so happy!!! thank you ALL for everything!!!!!